package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;

@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IUserService userService;

    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        Long userId = UserHolder.getUser().getId();
        String key="follow:"+userId;
        // 判断 关注 还是 取关 （新增用户或删除）
        if(isFollow){
            Follow follow = new Follow();
            follow.setFollowUserId(followUserId);
            follow.setUserId(userId);
            boolean isSuccess = save(follow);
            if(isSuccess){
                stringRedisTemplate.opsForSet().add(key,followUserId.toString());
            }
        }else {
            // 取关
            remove(new QueryWrapper<Follow>().eq("user_id", userId).eq("follow_user_id", followUserId));
            stringRedisTemplate.opsForSet().remove(key,followUserId.toString());
        }
        return Result.ok();
    }

    // 查询是否关注
    @Override
    public Result isFollow(Long followUserId) {
        Long userId = UserHolder.getUser().getId();
        Long count = query().eq("follow_user_id", followUserId).eq("follow_user_id", userId).count();
        return Result.ok(count>0);
    }

    @Override
    public Result followCommons(Long id) {
        Long userId = UserHolder.getUser().getId();
        String key1="follow:"+userId;
        String key2="follow:"+id;
        //求 关注的用户 的 交集
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(key1, key2);
        if(intersect==null||intersect.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        // 解析 id 集合
        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        Stream<UserDTO> users = userService.listByIds(ids).stream().map(user -> BeanUtil.copyProperties(user, UserDTO.class));
        return Result.ok(users);
    }
}
